1. Field of the Invention
The present invention relates to an apparatus and a method for supplying power in a mobile terminal. More particularly, the present invention relates to an apparatus and a method for controlling power supply according to a residual amount of a battery voltage.
2. Description of the Related Art
A mobile terminal operates using a battery. When the battery is completely charged, the battery has a voltage of 4.2V or 4.35V. The voltage of a battery is slowly reduced by the operation of the mobile terminal. If the voltage of the battery is reduced to a specific voltage, an operation of the mobile terminal is turned-off. The voltage threshold for turning-off the operation of the portable terminal is referred to as the cutoff voltage.
The length of time that a battery of the portable terminal can be used is determined based on the power and the battery capacity used in the system. Battery capacity refers to the difference in capacity between a maximum charge voltage and a cutoff voltage of a system. Even if the charge of a battery remains constant, the available capacity of the battery may differ according to the cutoff voltage. In general, the cutoff voltage of a feature phone is 3.3V, and the cutoff voltage of a smart phone is in the range of 3.4V to 3.5V. The cutoff voltage is a voltage where a system normally operates, and is always greater than or equal to the highest voltage used in the system. That is, if the highest voltage used in the portable terminal is 3.3V, the cutoff voltage is 3.3V or greater.
The highest voltage, except for display power and for On The Go (OTG) power, from among voltage used in the portable terminal (e.g., smart phone) is 3.3V. Accordingly, the cutoff voltage of most mobile terminals must be 3.3V or greater, and a corresponding cutoff operation of the system is performed at about 3.4V in consideration of voltage drop. In this case, although there may be more electric charge in the battery, certain operations of the system may be turned-off according to the system cutoff voltage.
Therefore, a need exists for an apparatus and a method for controlling the power supply in a mobile terminal according to a residual amount of a battery voltage.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.